Mercury-lamp-starting device.



J. L11. DEMPSTER. MERCURY LAMP STARTING DEVICE. APPLICATION FILED NOV 9, 1905. RENEWED APR. 4, 1908.

1,057,041. Patented Max:125, 1913.

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@WQLLW W/ TNESSES UNITED STATES PATENT orinon;

JOHN T. H. DEMPSTER, or SCHENEGTADY, new YORK, As smnon To Gamman ELECTRIC COMPANY, A conrona'rron or new ironic MEnoonY-LAMr-s'mwrmo nnvron.

Specif cation of Letters Patent. Patented .M: 25 1913 Application filed November 9, 1905, SerialNo. 286,515 Renewed April 4,,1908. SerialNo. 425,167.-

T all whom it may Con/007%.

I Be it known that 1, JOHN T. H. DEMP same, a citizen. of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Mercury- Lamp-Starting Devices, of which the following is a specification.

This invention relates to an attachment for mercury lamps or other vapor electric apparatus, by means of which such apparatus may be advantageously thrown in circnit and maintained in operative condition irrespective of the disturbing influence of other translating devices in'circuit;

' My invention also embodies various fea tures for .the protection of vapor electric apparatus during starting aswell as'when operating under normal working conditions.

10 .Although my invention is of general application it is of peculiar value when applied-to vapor lamps operating on a series circuit. y j

The details of my invention will be better understood by reference to the drawing forminga part of this specification.

The drawing shows a Well-known form of mercury vapor lamp equipped with my improved form of cut-indevice together with-other elements embodied in my present invention. v

The lamp shown in the drawing comprises an exhausted envelop 1 of glass, provided with a solid anode 2 of graphite and a cathode 3 of mercury or other suitable vaporizable material in which ,fioats a magnet-.

izable plunger 4 provided at its top with a small cup-shaped depression 5 filled with mercury. A high resistance filament 6 is 10 connected permanently to anode 2 and dips in the mercury of cup 5, thus completing an electric circuit through the. lamp when the'lamp is in its initial or. starting condition and before the mercury arc has been established within the tube. A solenoid 7 surrounds the lower part-f the lamp tube in such a way that whenlenergized by current it will draw down the plunger 1, and by so doing electrically disconnect the mer- 50 cury of cup 5 from the lowerend of filament 6': and thereby generate an are which serves to start the main arc of the tube in a manner Well understood to persons skilled in the art.

55. In shunt with the vapor tube is a film cut insulated arm '28 employed to liftcalrbon 16 of the lamp, and is provided with a movo5.

able armature 13, carrying an upwardly projecting arm 14 of conducting material to which is secured a contact block 15 for purposes hereinafter described. Two carbons 16 and 17 are so disposed that when an are 70, is drawn therebetween the arc shunts the mercury lamp. This arrangementis, effected by connecting the lower carbon 17 with the cut-out clip 9, and the upper carlien 16 with anode'fZ of the'lamp which in turn is connected to clip 10 of, the cut-out. s A double coil solenoid 18 is included directly in the line circuit to carbon 16, sothat when current flows between the carbons, or

through the lamp, or through the cut-out, this solenoid is energized. A U-shaped armature 19 has its two legs disposed in inductive relation to the two coils of solenoid 18, so that when current; passes through the; solenoid the armature is lifted. A dash pot 20 of ordinary form has its plunger 21 connected to armature 19, and thus serves to limit the freedom of motion of this armature and gives an appreciable time interval between the establishment of magnetislh fin the solenoid and the completed movement (if armature 19. This armature. carries'at its lower end a conducting arm 25 provided with a contact 26 adapted-under certain c611 ditions to engage with contact-15 of arfnature 13. A flexible conductor 27 connects armature 25 with clip 9 of the film cut-out. Armature 19 also supports an electrically from enga ement with the lower carbon when the apparatus is started. Engagement between the end of armature QS-and carbon 16 is effected bym'eans of the'clutch mechanism 29 pivoted at the'point 30,"sothat when arm 28 moves upward the clutch 29 firmly grips carbon '16, but -when the arm him its lowest position as shown in the drawing this clutch" mechanism strikes against a fixed stop 31 and releases-its on carbon 16, permltting the latter to slip I and start the generation of vapor before the thento 'carbon 17 and out through conductor 33. Solenoid 18 immediately begins to lift its armature 19, thereby separating the carbons and'establishing an arc in shunt with the vapor lamp, and consequently in shunt with film cut-out 9. As this are gradually increases in length the voltage impressed on the mercur lamp also increases but dashpot 20 so limits the movement of armature 19 that this increase across the lamp is relatively slow, thus giving the lamp ample time to draw down it's magnetizable plunger 4 voltage on the lamp reaches an abnormal value. When the lam starts, the current passes through solenold 12 and thus lifts contact 15 out of the path of contact 26, but if the lamp fails to start these two contacts finally engage, and thus establish a circuit in shunt with the lamp so that a metallic circuit is established directly between solenoid 18 and conductor 33, thus permanently cutting the lamp out of circuit.

The gradual increase in lamp voltage afforded by the shunting arc and its cooperating clash-pot is advantageous for several reasons which will be better understood by first considering certain peculiar, characteristics of vapor lamps and of series circuits including such lamps. The lamp shown in the drawing is provided with a high resistance filament 6 initially connecting the two electrodes and serving as a conducting path through the lam before the mercury arc is established. This filament is so designed that during normal operation it carries practically no current; as a consequence it gives the lamp an initial resistance much higher than its normal running resistance. -W ith several of these lamps directly in series on a circuit, the total initial resistance of the circuit is made much higher than the normal resistance, and in fact so much higher that difficulty has sometimes been experienced in making the generator build up, particu-.

larlywith generators of the Brush type. By the use, however, of the shunting arcs above described, the circuit is given an 1nitial resistance somewhat lowerthan its normal resistance, so that this diiiiculty is entirely overcome. The shunt arcs-also serve to protect the film cut-puts during the starting of the lamp, for if such cut-outs are properly adjusted to break down at a voltage somewhat above normal running voltage for the lamp, as for instance to break down at 80 volts, they would, if not protected by the carbon arc, break down during the starting operation of the vapor lamp when the drop between lamp terminals might reach 150 or 200 volts, because of the high resistance of the filament.

The movable element 4 of the lamp possesses a certain amount of inertia and makes it desirable to give to dash-pot 20 an action so sluggish that plunger 4 can perform its functions before the carbon arc reaches an abnormal length. I prefer to regulate, the time interval of this dash-pot by the fit of its plunger 21. I

As previously stated each lamp of the series circuit is equipped with its own sustained arc, dash-pot and other adjuncts, and I contemplate such an adjustment among the dash-pots that the lamps will not all startat once, but preferably will startone after another. This is advantageous in preventing one lamp from disturbing the action of the other lamps of the series, and also in preventing violent disturbances which might be present in the series circuit if all the lamps started at the same instant and consequently dropped simultaneously from high resistance to low resistance. This successive operation of the lamps is effected by giving different time constants to the different dash-pots of the series as may readily be done during manufacture by .varying the fit of the dash-pot plungers within their inclosing cylinders.

Vhat I claim as new and desire to secure by Letters Patent of the United States, is, 1. The combination of a series circuit, a plurality of'vapor electric devices connected to said circuit, and automatic means for preventing the simultaneous starting of said vapor electric devices when said circuit is energiz'ed.

2. The combination ofa series circuit, a plurality of electric devices connected there- 'to, a shunt path for each of said vapor devices, means for increasing the resistance of said shunt paths, and retarding means for preventing simultaneous increase in the resistance of said shunt paths.

.3. The combination of a series c rcuit, a

Ill

plurality of vapor electric devices connected .121

thereto, means for establishing an arc in shunt with each of said devices and for increasing the Iengthof each of said arcs to increase the voltage on saidvapor devices. and retarding means for preventing simultaneous mcrease 1n the-lengthof sald arcs.

- 4. The combination of, a series circuit, a

plurality of vapor electric devices connected thereto, means for. establishing an arc in shunt with each of said devices and for increasingthe length of said arcs, and a dashpot associated with each of said arcs to prevent, a sudden increase in lengthlthereof,

said dash-pots being adjusted with differentretarding powers to prevent simultaneous starting of said vaporelectric devices.

4 5. The combination of a vapor electric device comprlsmg an evacuated envelo and electrodes therein, of means for esta lishsaid vapor device and for increasing the length of said shunting arc toincrease the voltage on said vapor device at starting, and

retarding means for preventing a sudden in- I .crease in the length of said shunting arc.

7 The combination with a vapor device having a plurality of electrodes and starting means for establishing an arc betweensaid electrodes, said starting means having an appreciable inertia, of means for establishing an arc in shunt with said vapor device and. for increasing the length. of said lastnamed arc to increase the voltage across said vapor, device, and means for retarding said ncrease in voltage 'to glve sa1d starting 'jmea-ns time for advantageous operation.

.18. The combination of a vapor electric device, a distribution circuit for supplying energy thereto, a film cut-out in shunt with said device, contacts initially shunting said film cut-out and protecting it from the disruptive action of "said distribution circuit,

and means for increasing the distance between said contacts to increase the voltage on said vapor device at starting.

9. The combination with a vapor electric device, of means for establishing a sustained arc in shunt with said device and for automatically increasing the length of said are to simultaneously increase the voltage on said device at starting;

, 10. The combination of a vapor lamp, a conducting path in shunt with said lamp, and means for producing an arc in said shunt path and for gradually increasing the length of said are to gradually increase the voltage on said vapor lamp. 11. The combination with a vapor lamp of arcing contacts connected to the termina-ls of said lamp, andautomatic means for gradually moving said contacts to produce a sustained arc and gradually increase the voltage across the terminals of the lamp.

'12. The combination of a plurality of mercury vapor lamps connected in series, and automatic means for starting said lamps in predetermined succession, each lamp being started on a potential higher-than its normal operating potential.

13. The combination of a plurality of mercury vapor lamps disposed in series, of means for shunting each of said lamps, and automatic means for successively opening the shunt path for said lamps to start the lamps one after order.

14. A system comprising vapor electric devices disposed 1n series and automatic means .for starting said devices successively in a predetermined order. I

15. In a series lighting circuit containing mercury vapor arc lamps, means for supplying a high voltage successively and automatically to each of the lamps in series to start the same.

In witness whereof, I have hereunto set my hand this 8th day of November, 1905.

JOHN T. DEMPSTER.

Witnesses:

.BENJAMIN B. HULL, MARGARET E. WOOLLEY.

another in a predetermined 

